Solar panel mounting stand installation method, pile and solar panel mounting stand

ABSTRACT

A method of installing a solar panel mounting stand, the method including: forming an installation scheduled surface on which a plurality of piles are scheduled to be installed at a position deeper than an original ground surface, by digging the soil of an installation site of the solar panel mounting stand; installing the plurality of piles at the installation site by supporting the plurality of piles in a state of being relatively aligned, using a pile installation structure, and transporting the plurality of piles to the installation site of the solar panel mounting stand integrally with the pile installation structure, and placing the projecting portions on the installation scheduled surface corresponding to each projecting portion, and refilling the installation site with soil; removing the pile installation structure from the plurality of piles; and assembling a member as a framework of the solar panel mounting stand, using the plurality of piles.

BACKGROUND

1. Technical Field

The present invention relates to a method of installing a solar panelmounting stand for mounting solar power generation panels (hereinafter,referred to as “solar panels”) to generate electric power by means ofsunlight, piles preferably used therefor, and solar panel mountingstands using the piles.

2. Background Art

Recently, for the purpose of preventing a global warming, solar-powerplants represented by “mega solar” have been constructed. In suchsolar-power plants, a large number of solar panel mounting stands aregenerally installed on the ground (on the soil), and a plurality ofsolar panels are mounted to each solar panel mounting stand.

A solar panel mounting stand uses, for example, a concrete foundation asa base. However, to use a concrete foundation as a base, cost and laborrequired for the installation of solar panel mounting stands areenormous.

Therefore, conventionally, instead of using a concrete foundation, forexample, a technology described in patent document 1 has been known.According to this conventional technology, the lower end of thesupporting leg of the solar panel mounting stand is equipped with aprojecting portion, a posthole is created in the projecting portion, anda pile is driven into the ground through the posthole, thereby securelyfixing the supporting leg into the ground.

PRIOR ART DOCUMENT

[Patent Document]

[Patent document 1] Japanese Unexamined Patent Application PublicationNo. 2003-69062

However, the aforementioned conventional technology has the followingproblems:

That is, when installing solar panel mounting stands on the ground, theinstallation site is not always suitable for the installation of solarpanel mounting stands.

Therefore, driving piles is sometimes difficult, for example, dependingon the ground condition of the installation site. Specifically, whendriving piles into the ground mainly composed of sand, the sand istamped down during the piling process, which makes it difficult to drivepiles deeply into the ground. The construction test conducted by theinventors of the present invention has proven that existing piles can bedriven into the ground only 50-cm deep at a location having an N value,indicating the hardness of the sand ground of 10 or more. If a pile isnot driven into the ground deep enough, when a lifting force isgenerated due to wind pressure imposed on the solar panels, the pile iseasily removed. Furthermore, there is also a well-known pile designedsuch that the lower end of the pile is formed into a spiral-shapedportion, and the pile is screwed into the ground by using thespiral-shaped portion. However, the cost of this type of pile(hereinafter, referred to as “spiral pile”) is very high. Also, it takesa considerable amount of time and labor to drive spiral piles into theground on site. Accordingly, material cost and construction costrequired for the installation of solar panel mounting stands become veryhigh, resulting in enormous total cost.

A main objective of the present invention is to provide a method ofinstalling a solar panel mounting stand capable of significantlyreducing the cost and labor to install solar panel mounting stands andalso provide piles preferably used therefor.

Generally, it is common knowledge that piles used for civil engineeringwork are driven into the ground (spiral piles are screwed into theground). The inventors of the present invention have devised the presentinvention as the result of an alternative way of thinking about pilesbeyond what is commonly known. That is, they disregarded the commonunderstanding that “piles are driven into the ground” and conceived anidea of “placing piles” which means that piles are placed in the groundinstead of being driven into the ground. However, when piles are used assupporting legs of a solar panel mounting stand, simply placing thepiles in the ground will not withstand the lifting force generated bythe application of wind pressure.

On the other hand, most of solar panels mounted to solar panel mountingstands are light enough so that one or more workers can manually liftthe panels. Therefore, for example, even when a plurality of solarpanels are mounted to one solar panel mounting stand, the load appliedon the solar panel mounting stand is not so heavy.

In light of such circumstances, the inventors of the present inventionhave realized that a requirement for the solar panel mounting stand isto maintain the condition in which the solar panel mounting stand issecurely fixed (immobilized) when a lifting force is generated due towind pressure imposed on the solar panels, rather than the mechanicalstrength that supports the weight of the solar panels; and the inventorshave focused attention on the piles used as supporting legs and devisedthe present invention. Hereinafter, preferred embodiments of the presentinvention will be described.

SUMMARY OF THE INVENTION

A first aspect of the present invention provides a method of installinga solar panel mounting stand using a pile as a supporting leg, the pileincluding: a columnar pile body, at least a lower end side thereof beingburied in the soil when a solar panel mounting stand equipped with aplurality of supporting legs is installed on the ground; and anon-spiral-shaped projecting portion provided at a lower end of the pilebody in a state projected in a radial direction of the pile body—andconfigured to inhibit a pull-off of the pile body under a load of thesoil when the lower end side of the pile body is embedded in the soil;

the method including:

a first step of forming an installation scheduled surface on which theplurality of piles are scheduled to be installed at a position deeperthan an original ground surface, by digging the soil of an installationsite of the solar panel mounting stand;

a second step of installing the plurality of piles at the installationsite by supporting the plurality of piles in a state of being relativelyaligned, using a pile installation structure, and while maintaining sucha supporting state, transporting the plurality of piles to theinstallation site of the solar panel mounting stand integrally with thepile installation structure, and placing the projecting portions, whichare formed at lower ends of the plurality of piles, on the installationscheduled surface corresponding to each projecting portion, andthereafter refilling the installation site with soil;

a third step of removing the pile installation structure from theplurality of piles; and

a fourth step of assembling a member as a framework of the solar panelmounting stand, using the plurality of piles.

A second aspect of the present invention provides a solar panel mountingstand installation method according to the first aspect, wherein in thesecond step, the pile installation structure supporting the plurality ofpiles, is hoisted by a crane and transported to the installation site ofthe solar panel mounting stand.

A third aspect of the present invention provides a pile used as asupporting leg when a solar panel mounting stand equipped with aplurality of supporting legs is installed, including:

a columnar pile body; and

a non-spiral-shaped projecting portion provided at a lower end of thepile body in a state projected in a radial direction of the pile body,

wherein at least a lower end side of the pile body is buried in the soilwhen the solar panel mounting stand is installed; and

the projecting portion is configured to inhibit a pull-off of the pilebody under a load of the soil when the lower end side of the pile bodyis embedded in the soil.

A fourth aspect of the present invention provides the pile according tothe third aspect, wherein the projecting portion is formed into aplate-like shape having a larger external size than an outer diameter ofthe pile body.

5. The pile according to the third aspect or the fourth aspect, whereina coupling portion is provided on an upper end of the pile body, forassembling a member as a framework of the solar panel mounting stand.

A sixth aspect of the present invention provides a solar panel mountingstand equipped with a plurality of supporting legs, wherein

a pile is used as a supporting leg, said pile comprising:

a columnar pile body, at least a lower end portion thereof being buriedin the soil; and

a non-spiral-shaped projecting portion provided at a lower end of thepile body in a state projected in a radial direction of the pile body,and configured to inhibit a pull-off of the pile body under a load ofthe soil when the lower end side of the pile body is embedded in thesoil.

According to the present invention, it is possible to significantlyreduce cost and labor required for the installation of solar panelmounting stands.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a configuration example of a pile according to anembodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1.

FIG. 3 is a cross-sectional view taken along the line B-B of FIG. 1.

FIG. 4 is a front view showing a configuration example of a solar panelmounting stand according to an embodiment of the present invention.

FIG. 5 is a plan view showing a configuration example of a solar panelmounting stand according to an embodiment of the present invention.

FIG. 6 is a side view showing a configuration example of a solar panelmounting stand according to an embodiment of the present invention.

FIG. 7 is an enlarged view of a panel supporting rack (triangular rack).

FIG. 8 is a front view showing a configuration example of the structurefor pile installation according to an embodiment of the presentinvention.

FIG. 9 is a plan view showing a configuration example of the structurefor pile installation according to an embodiment of the presentinvention.

FIG. 10 is a side view showing a configuration example of the structurefor pile installation according to an embodiment of the presentinvention.

FIG. 11 illustrates the configuration of the connecting fitting.

FIG. 12 is an explanatory diagram (part 1) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 13 is an explanatory diagram (part 2) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 14 is an explanatory diagram (part 3) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 15 is an explanatory diagram (part 4) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 16 is an explanatory diagram (part 5) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 17 is an explanatory diagram (part 6) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 18 is an explanatory diagram (part 7) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 19 is an explanatory diagram (part 8) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 20 is an explanatory diagram (part 9) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 21 is an explanatory diagram (part 10) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 22 is an explanatory diagram (part 11) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 23 is an explanatory diagram (part 12) for illustrating the methodof installing a solar panel mounting stand according to an embodiment ofthe present invention.

FIG. 24 is a front view showing solar panels mounted to a solar panelmounting stand.

FIG. 25 is a side view showing solar panels mounted to a solar panelmounting stand.

FIGS. 26A, 26B, 26C AND 26D show specific structural examples whererespective members are fastened by bolts and nuts.

FIG. 27 illustrates an adverse condition occurring when piles are driveninto the undulating ground.

FIG. 28 illustrates the superior condition in which piles according tothis embodiment are installed in the undulating ground.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings.

Embodiments of the present invention will be described according to thefollowing sequential order:

1. Configuration of a pile according to an embodiment of the presentinvention

2. Configuration of a solar panel mounting stand according to anembodiment of the present invention

3. Configuration of a structure for pile installation according to anembodiment of the present invention

4. A method of installing a solar panel mounting stand according to anembodiment of the present invention

5. Advantageous effects of the embodiment of the present invention

6. Modified example, etc.

7. Other preferred embodiments of the present invention

1. Configuration of a Pile According to an Embodiment of the PresentInvention

FIG. 1 shows a configuration example of a pile according to anembodiment of the present invention. FIG. 2 is a cross-sectional viewtaken along the line A-A of FIG. 1, and FIG. 3 is a cross-sectional viewtaken along the line B-B of FIG. 1.

The pile 1, shown in the drawing, roughly comprises a pile body 2, aprojecting portion 3, and a coupling portion 4.

The pile body 2 is entirely formed into a column. The cross section ofthe pile body 2 is circular. The pile body 2 can be formed, for example,by using a straight steel pipe (single pipe, etc.). The length of thepile body 2 is specified, for example, within a range between 2 m and 4m by taking into account the length that is buried in the ground (in thesoil) and the length that protrudes above the ground. The outer diameterof the pile body 2 is specified, for example, within a range of 40 mm ormore and 60 mm or less by taking into account the load applied to thepile body 2.

The projecting portion 3 is provided at the lower end of the pile body 2in the longitudinal direction of the pile body 2. The lower end of thepile body 2 is the end that is disposed downward when the pile 1 isinstalled in the ground. The projecting portion 3 is provided such thatit projects in the radial direction of the pile body 2. The projectingportion 3 has the external size that is larger than the outer diameterof the pile body 2. The projecting portion 3 is formed into anon-spirally shape. In this embodiment, as an example of a non-spirallyshape, the projecting portion 3 is formed into a flat plate.

By providing such a plate-like projecting portion 3 at the lower end ofthe pile body 2, it is indicated that the pile 1 is not intended to bedriven or screwed into the ground for the installation. In this respect,this pile is completely different from other known piles. That is,normally, the lower end of the pile is formed into a thin conical shapeto facilitate piling into the ground, or a spiral-shaped portion isprovided at the tip of the pile to enable the pile to be screwed intothe ground; however, in this embodiment, the lower end of the pile body2 is equipped with a projecting portion 3 shaped such that it hindersthe pile from being driven or screwed into the ground. The projectingportion 3 can be formed using a square steel plate, for example. Theaforementioned pile body 2 is disposed at the central part of theprojecting portion 3 when viewed from the direction of the central axisof the pile 1. The projecting portion 3 is, for example, fixed to thelower end of the pile body 2 by welding or a similar means. Of surfaces3 a and 3 b of the projecting portion 3, one surface 3 a is disposedupward and the other surface 3 b is disposed downward when the pile 1 isinstalled. At the time of back-filling with soil, described later, onesurface (hereinafter, also referred to as the “upper surface”) 3 a ofthe projecting portion 3 is the surface that receives the load (weightpressure) of the soil, and the other surface (hereinafter, also referredto as the “lower surface”) 3 b is the surface that comes in contact with(contacts) the ground at the scheduled installation site describedlater.

The coupling portion 4 is provided at the upper end of the pile body 2in the longitudinal direction of the pile body 2. The upper end of thepile body 2 is the end that is disposed upward when the pile 1 isinstalled in the ground. The coupling portion 4 is provided so as tomount a member (described later), which serves as a framework of thesolar panel mounting stand, to the pile 1. Similar to the aforementionedprojecting portion 3, the coupling portion 4 is provided such that asquare steel plate is fixed to the upper end of the pile body 2 bywelding or a similar means. The coupling portion 4 is disposed so thatit is opposite of the projecting portion 3 with the pile body 2interposed. Furthermore, at both ends of the pile body 2, the couplingportion 4 and the projecting portion 3 are disposed parallel. Similar tothe projecting portion 3, the coupling portion 4 is provided such thatit projects in the radial direction of the pile body 2. The projectingportion 3 of the coupling portion 4 has four through-holes 4 a. Eachthrough-hole 4 a is provided at each corner of the coupling portion 4.The external size of the coupling portion 4 is smaller than the externalsize of the projecting portion 3. As an example, when the projectingportion 3 and the coupling portion 4 are each made of a flat squareplate, the external size of the coupling portion 4 is specified suchthat the length of one side is, for example, within a range of 150 mm ormore and 200 mm or less, and the external size of the projecting portion3 is specified such that the length of one side is, for example, withina range of 300 mm or more and 600 mm or less. Furthermore, the thicknessof the projecting portion 3 and the coupling portion 4 (thickness of theplate) is each specified, for example, within a range of 4 mm or moreand 8 mm or less. The surface of the pile 1 is rustproofed by means ofmolten zinc plating, etc.

2. Configuration of a Solar Panel Mounting Stand According to anEmbodiment of the Present Invention

FIG. 4 is a front view showing a configuration example of a solar panelmounting stand according to an embodiment of the present invention, FIG.5 is a plan view, and FIG. 6 is a side view of the same. Moreover, theinverted triangle mark in FIG. 4 and FIG. 6 indicates the assumedsurface of the ground on which the solar panel mounting stand 10 is tobe installed.

The solar panel mounting stand 10, shown in the drawing, roughlycomprises a plurality of supporting legs 11 to serve as members thatform the foundation of the mounting rack, and a plurality of panelsupporting racks 12, a plurality of beam members 13, a plurality ofbrace members 14, 15, and 16, and a plurality of panel receiving members17 to serve as members that form the framework of the mounting rack.Herein, as an example, one solar panel mounting stand 10 is made up ofsix supporting legs 11, three panel supporting racks 12, two beammembers 13, three brace members 14, 15, and 16, and twelve panelreceiving members 17. However, the number of members, dimensions andarrangement thereof can be flexibly changed according to the number andthe external size of the solar panels mounted to one solar panelmounting stand 10. The surface of each member is rustproofed (e.g.,molten zinc plating for steel members).

Supporting legs 11 form the foundation of the solar panel mounting stand10. The supporting leg 11 is constituted using the aforementioned pile1. That is, the supporting leg 11 integrates the aforementioned pilebody 2, projecting portion 3, and the coupling portion 4. Wheninstalling a solar panel mounting stand 10, the lower end of eachsupporting leg 11 is buried in the ground.

The panel supporting rack 12 is a triangular rack (triangle rack) thatobliquely supports solar panels. The panel supporting rack 12 is mountedonto the aforementioned supporting legs 11. When installing solar panelson the ground using a solar panel mounting stand 10, the solar panelsare mounted to the solar panel mounting stand 10 in such a way that theyare inclined at a predetermined angle (e.g., about 30 degrees) withregard to the horizontal plane that is perpendicular to the verticalplane (hereinafter, referred to as the “horizontal plane”). Therefore,the panel supporting rack 12 forms a right triangle having the obliqueside that corresponds to the solar panel installation angle. The panelsupporting rack 12 is made up of three members that form a righttriangle. In this embodiment, as a preferred example, as shown in FIG.7, the three members are made of steel (e.g., channel steel) 12 a, 12 b,and 12 c, and the steel members 12 a, 12 b, and 12 c are fixed to oneanother by welding or a similar means, thereby forming an integratedpanel supporting rack 12.

Of the three steel members 12 a, 12 b, and 12 c, the steel member 12 aforms the base of a right triangle, the steel member 12 b forms thevertical side of the right triangle, and the steel member 12 c forms theoblique side of the right triangle. The “base” described herein is thehorizontally located side when the panel supporting rack 12 is mountedonto the aforementioned supporting legs 11, and the “vertical side” isthe vertically (perpendicularly) located side when the panel supportingrack 12 is mounted onto the supporting legs 11. The “oblique side” isthe “side opposite to the right angle”, as mathematically defined, whichis obliquely located when the panel supporting rack 12 is mounted ontothe supporting legs 11. The lower-level end of the steel member 12 cprotrudes such that it obliquely extends downward beyond the end of thesteel member 12 a. The upper-level end of the steel member 12 cprotrudes such that it obliquely extends upward beyond the upper end ofthe steel member 12 b.

One end of the steel member 12 a is equipped with a mounting plate 18,and the other end oppositely located is also equipped with anothermounting plate 18. Respective mounting plates 18 are used to mount apanel supporting rack 12 onto two supporting legs 11 that are adjacentto each other in the lateral direction of the solar panel mounting stand10. The two mounting plates 18 are disposed in the longitudinaldirection of the steel member 12 a at a predetermined distance (the samedistance as the clearance between two piles 1 that are adjacent to eachother in the lateral direction of the solar panel mounting stand 10).The mounting plate 18 is made of a flat steel plate that is shaped tofit the external size of the aforementioned coupling portion 4. When themounting plate 18 and the coupling portion 4 are each made of aplate-like member of the same external size, positioning becomes easywhen mounting the panel supporting rack 12 onto the piles 1. Themounting plate 18 has four through-holes that have the same positionalrelationships as the holes in the coupling portion 4. Therefore, whenthe mounting plate 18 is placed on top of the aforementioned couplingportion 4, the corresponding through-holes are disposed concentrically(ideal state). At one end of the steel member 12 a, a mounting plate 18is fixed to the lower surface of the steel member 12 a by welding or asimilar means. Also, at the other end of the steel member 12 a, anothermounting plate 18 is fixed to the lower surface of the steel member 12 aand also to the lower end of the steel member 12 b by welding or asimilar means. Furthermore, the steel member 12 b has through-holes (notshown) to mount brace members 14 and 15, and the steel member 12 c hasthrough-holes (not shown) to mount beam members 13.

The beam member 13 is mounted so that it connects together three panelsupporting racks 12. The beam member 13 can be formed using a long steelmember (e.g., lip groove steel), for example. Both ends of the beammember 13 are disposed such that they protrude outward from respectivepanel supporting racks 12 (lateral to the solar panel mounting stand10). Respective beam members 13 are disposed parallel in thelongitudinal direction of the solar panel mounting stand 10. One beammember 13 is fixed to the upper-level end of the steel member 12 c ofthe panel supporting rack 12 by using bolts and nuts. The other beammember 13 is fixed to the lower-level end of the steel member 12 c byusing bolts and nuts.

Brace members 14 and 15 are designed to mainly inhibit a solar panelmounting stand 10 from rocking in the longitudinal direction of thesolar panel mounting stand 10. The brace member 14 is mounted such thatit connects together respective steel members 12 b of the central panelsupporting rack 12 and the one-end side panel supporting rack 12, amongthree panel supporting racks 12 disposed in the longitudinal directionof the solar panel mounting stand 10. On the contrary, the brace member15 is mounted such that it connects together respective steel members 12b of the central panel supporting rack 12 and the the-other-end sidepanel supporting rack 12. Those brace members 14 and 15 are disposedsuch that they form a mountain shape when the solar panel mounting stand10 is viewed from the front. That is, the brace member 14 is obliquelydisposed from the central panel supporting rack 12 to the one-end sidepanel supporting rack 12 so that it becomes gradually inclined; and thebrace member 15 is obliquely disposed from the central panel supportingrack 12 to the the-other-end side panel supporting rack 12 so that itbecomes gradually inclined. The brace members 14 and 15 can be formedusing long steel members (e.g., L-shaped steel), for example. One endand the other end of respective brace members 14 and 15 are fixed to thesteel members 12 b of the corresponding panel supporting racks 12 byusing bolts and nuts, for example.

On the other hand, the brace member 16 is designed to mainly inhibit thesolar panel mounting stand 10 from rocking in the lateral direction. Thebrace member 16 is mounted such that it connects together two supportinglegs 11 that support from below the central panel supporting rack 12.Furthermore, the brace member 16 is disposed such that it is inclined inthe same direction as the steel member 12 c of the panel supporting rack12. Therefore, the brace member 16 is obliquely disposed so that itbecomes gradually inclined from the back to the front when the solarpanel mounting stand 10 is viewed from the front. The brace member 16can be formed, for example, by using the same steel (e.g., L-shapedsteel) as the aforementioned brace members 14 and 15. One end and theother end of the brace member 16 are fixed to the correspondingsupporting legs 11 by using bolts and nuts, for example.

Panel receiving members 17 hold and support solar panels. A solar panelis equipped with a frame member made of aluminum, etc., for example, andthe frame member can be mounted to the panel receiving members 17 byusing bolts and nuts, for example. The panel receiving member 17 can beformed using a long steel member (e.g., lip groove steel), for example.

A plurality of panel receiving members 17 are mounted in thelongitudinal direction of the solar panel mounting stand 10 atappropriate intervals. The panel receiving members 17 are mounted suchthat they extend across two beam members 13. The panel receiving member17 is inclined with regard to the horizontal plane. The inclined angleof the panel receiving member 17 is the same as that of the steel member12 c of the panel supporting rack 12. One end of the panel receivingmember 17 protrudes obliquely upward beyond the beam member 13 locatedbelow on the upper-level side. The other end of the panel receivingmember 17 protrudes obliquely downward beyond the beam member 13 locatedbelow on the lower-level side. With the configuration in which both endsof the panel receiving member 17 thus protrude, it is possible to mounta larger number of solar panels to one solar panel mounting stand 10.Intervals among panel receiving members 17 that are adjacent to oneanother in the longitudinal direction of the solar panel mounting stand10 are determined corresponding to the mounting holes provided in theframe member of the solar panels. Incidentally, solar panels aredesigned to be disposed (laid) in a reticular pattern using a pluralityof panel receiving members 17.

3. Configuration of a Structure for Pile Installation According to anEmbodiment of the Present Invention

FIG. 8 is a front view showing a configuration example of the structurefor pile installation according to an embodiment of the presentinvention, FIG. 9 is a plan view, and FIG. 10 is a side view of thesame.

Upon installation of the solar panel mounting stand 10 on the ground,the structure 20, shown in the drawing, is designed to be used toinstall a plurality of piles 1 that serve as supporting legs 11 of thesolar panel mounting stand 10. The structure 20 roughly comprises aplurality of lower-tier transverse beams 21, a plurality of supportingposts 22, a plurality of upper-tier transverse beams 23, and onevertical beam 24. Herein, as an example, one structure 20 comprisesthree lower-tier transverse beams 21, six supporting posts 22, threeupper-tier transverse beams 23, and one vertical beam 24. However, thenumber, dimensions and arrangement of the members can be changedaccording to the number and arrangement of the piles 1 to be supported.

The lower-tier transverse beam 21 can be formed by using I-shaped steel,for example. Plate-like connecting fittings 25 are provided respectivelyon both ends of the lower-tier transverse beam 21 in the longitudinaldirection. When piles 1 are mounted on the structure 20, the connectingfittings 25 are detachably connected to the piles 1. Respectiveconnecting fittings 25 are fixed to the lower surface of the lower-tiertransverse beam 21 by welding or a similar means. A part of theconnecting fitting 25 protrudes from the lower-tier transverse beam 21,and a notched portion 26, as shown in FIG. 11, is formed on theprotruding portion. In FIG. 11, the portion within the broken linerepresented by number 21 indicates the welded portion that connects theconnecting fitting 25 to the lower-tier transverse beam 21. The notchedportion 26 allows the connecting fitting 25 to be mounted on anddetached from a pile 1. Notched portions 26 of respective connectingfittings 25 are disposed in the same direction (one direction) in thelongitudinal direction of the vertical beam 24. One side of the notchedportion 26 (open side) is wide open so that it can easily direct thepile 1 to the back side of the notched portion 26.

Furthermore, the connecting fitting 25 has two through-holes 27. Thosethrough-holes 27 are disposed with the notched portion 26 interposed.Each through-hole 27 is intended for mounting a brace 28 on theconnecting fitting 25. For a brace 28, a clamp (metal bar member that isbent in a nearly horseshoe shape) can be used, for example. The brace 28relatively fixes the pile 1 to the connecting fitting 25 by insertingboth ends of the brace 28 into the two through-holes 27 while the pile 1is engaged with the notched portion 26 of the connecting fitting 25.

The supporting post 22 can be formed using H-shaped steel, for example.The supporting post 22 vertically stands on the lower-tier transversebeam 21. The number of supporting posts 22 is the same as the number ofpiles 1 simultaneously supported by the structure 20. Both ends (upperand lower ends) of the supporting post 22 are fixed to the correspondinglower-tier transverse beam 21 and upper-tier transverse beam 23 by usingbolts and nuts, for example.

The upper-tier transverse beam 23 is formed by using H-shaped steel, forexample. The upper-tier transverse beam 23 is disposed directly abovethe lower-tier transverse beam 21 parallel to the lower-tier transversebeam 21. The upper-tier transverse beam 23 has holes into which thecoupling portions 4 of respective piles 1 are fitted. Furthermore, asnecessary, a reinforcing plate 30 is mounted to each corner portionformed by the upper-tier transverse beam 23 and the supporting post 22.

The vertical beam 24 can be formed by using H-shaped steel, for example.The vertical beam 24 is mounted so as to connect together threeupper-tier transverse beams 23. The vertical beam 24 is mounted onrespective upper-tier transverse beams 23 using bolts and nuts, forexample, while the vertical beam 24 is placed on the upper surfaces ofrespective upper-tier transverse beams 23. Two metal hangers 29 areprovided on the upper surface of the vertical beam 24. Those metalhangers 29 are disposed in the longitudinal direction of the verticalbeam 24 at appropriate intervals.

Moreover, in FIG. 9, the intersection point indicated by the “X”provided at both ends of the upper-tier transverse beam 23 is theposition where the central axis of the pile 1 is located when the pile 1is mounted on the structure 20.

4. A Method of Installing a Solar Panel Mounting Stand According to anEmbodiment of the Present Invention

Next, a method of installing a solar panel mounting stand according toan embodiment of the present invention will be described with referenceto FIG. 12 to FIG. 23.

First, upon installing the aforementioned solar panel mounting stand 10on the ground, the soil (including sand) at the installation site is dugout. In this document, regardless of the size of particles constitutingthe soil, the term “soil” is used in a broad sense. When digging in thesoil at the installation site of the solar panel mounting stand 10, theentire installation site may be dug out at a uniform depth. However, asthe size of the solar panel mounting stand 10 increases, the area of thelocation at which the soil is dug out also increases accordingly.Therefore, it takes time and labor for the excavating work. For thisreason, when digging out the soil at the installation site of the solarpanel mounting stand 10, it is preferred that, over the entireinstallation site, only the soil at the exact locations at which aplurality of (six in this embodiment) piles 1 are scheduled to beinstalled should be removed. This construction method is adopted in thisembodiment. However, in that case, the side wall of hole H (see FIG. 12)tends to be collapsed during the excavating work depending on the typeof the soil at the installation site. Therefore, it is desirable thatthe soil of the scheduled installation site of the pile 1 be dug out toa desired depth while preventing the hole H from collapsing by usingsquare blocks. The excavation depth may be determined within a rangebetween 1 m to 3 m, for example, although it depends on the weight andsize of the solar panel mounting stand 10, weight of the solar panel,length of the pile 1, size of the projecting portion 3, etc.

By thus digging out the soil, at the installation site of the solarpanel mounting stand 10, the planned installation ground surface 19 onwhich a pile 1 is scheduled to be installed can be formed at a depthdeeper than the original ground G (ground surface before digging out) asshown in FIG. 12. The planned installation ground surface 19 is exposedat the bottom of the hole H after the soil is dug out. The number ofplanned installation ground surfaces 19 is equal to the number of piles1 to be installed and formed at the installation site of the solar panelmounting stand 10. Furthermore, it is desirable that leveling beconducted so that respective planned installation ground surfaces 19 canbe at the same depth, with a common virtual horizontal plane as areference.

Next, using the aforementioned structure 20, a plurality of (six in thisembodiment) piles 1 are supported so that they are relativelypositioned. The condition described herein as “relatively positioned” isthe condition in which a plurality of piles 1 are positioned so thatthey have predetermined positional relationships (defined by design).

When supporting a plurality of piles 1 by the structure 20, respectivepiles 1 are mounted on the structure 20 as described below. That is,while the pile body 2 of a pile 1 is engaged with the notched portion 26of the connecting fitting 25, the coupling portion 4 of the pile 1 isfixed to a predetermined location of the upper-tier transverse beam 23by using bolts and nuts. Thereafter, the brace 28 is inserted from aboveinto the through-hole 27 of the connecting fitting 25. By doing so, aplurality of piles 1 are integrally supported by the structure 20. Theterm “integrally” described herein means that “so that the structure 20and a plurality of piles 1 are immobilized”.

FIG. 13 is a front view showing the piles 1 mounted to the structure 20,and FIG. 14 is a side view of the same. Furthermore, when mounting piles1 to the structure 20, whether the plurality of piles 1 are in theprescribed positional relationships is confirmed as needed, and based onthe result, fine adjustments of the positions at which piles 1 aremounted may be made.

Next, as shown in FIG. 15, a wire 40 is attached to two metal hangers 29of the vertical beam 24, and by hoisting the wire 40 by a crane, aplurality of piles 1 are hoisted integrally with the structure 20 whilethe aforementioned support condition is maintained. Next, by moving andturning a crane, the hoisted structure 20 and the plurality of piles 1are transported to the installation site of the solar panel mountingstand 10. At the installation site, as shown in FIG. 12, plannedinstallation ground surfaces 19 formed at the scheduled installationsites of the piles 1 are aligned with the positions of the correspondingpiles 1, and the piles 1 are lowered together with the structure 20 bythe crane; and then, as shown in FIG. 16, the lower end (the lowersurface 3 b of the projecting portion 3) of each pile 1 comes in contactwith the corresponding planned installation ground surface 19.

Next, as shown in FIG. 17 and FIG. 18, locations at which respectivepiles 1 were installed (in hole H in this embodiment) are refilled withthe soil. Thus, the projecting portion 3 of the pile 1 is covered withsoil and the lower end portion of the pile 1 is buried in the soil. Atthis time, the refilling soil is compacted as necessary. The soilrefilling work should be conducted while the plurality of piles 1 aresupported by the structure 20.

This is because relative positional relationships of the plurality ofpiles 1 can be maintained even if a small amount of force is imposed onthe piles 1 during a refilling process of the soil.

Thus, a plurality of piles 1 are installed at the installation site ofthe solar panel mounting stand 10.

Moreover, the soil that has been dug out to form the plannedinstallation ground surfaces 19 can be used for the refilling use.However, the soil used for refilling does not have to be the same soilthat has been dug out.

Next, the structure 20 is removed from the plurality of piles 1.Specifically, the bolts and nuts that fasten the coupling portions 4 ofrespective piles 1 to the upper-tier transverse beams 23 are removed.Furthermore, braces 28 are removed from respective connecting fittings25. Next, the entire structure 20 is horizontally moved to the oppositeside of the opening of the notched portion 26 of the connecting fitting25. Thus, the structure 20 is separated from the respective piles 1. Acrane is used to move the structure 20. Thereafter, the structure 20 ishoisted by a crane and transported to a location distant from theinstallation site of the solar panel mounting stand 10. As a result, atthe installation site of the solar panel mounting stand 10, as shown inFIG. 19, a plurality of (six in this embodiment) piles 1 are installedvertically (perpendicularly) upright. At this time, if the lengths ofall piles 1 are the same, coupling portions 4 of respective piles 1 aredisposed on the same virtual plane. Thus, the installed piles 1 serve assupporting legs 11 of the solar panel mounting stand 10.

Next, using a plurality of piles 1, members that constitute a frameworkof the solar panel mounting stand 10 are assembled. Member mounting workis conducted as described below.

First, as shown in FIG. 20, panel supporting racks 12 are mounted on thepiles 1. At this time, one panel supporting rack 12 is mounted on twopiles 1 that are adjacent to each other in the lateral direction of thesolar panel mounting stand 10. Since two mounting plates 18 (see FIG. 7)are mounted on the lower surface of the steel member 12 a of the panelsupporting rack 12, the panel supporting rack 12 is placed on two piles1 so that respective mounting plates 18 are placed on the couplingportions 4 of the respective piles 1. At that time, holes of thecoupling portion 4 and those of the mounting plate 18 are aligned, and abolt is inserted into each aligned hole and fastened by nuts. Thus, onepanel supporting rack 12 is fixed to two piles 1. This mounting work isconducted for three panel supporting racks 12.

Next, as shown in FIG. 21, beam members 13 are installed on the panelsupporting racks 12. The beam members 13 are mounted on three panelsupporting racks 12 disposed in the longitudinal direction of the solarpanel mounting stand 10 using bolts and nuts, for example. Holes usedfor mounting are provided beforehand in the panel supporting racks 12and the beam members 13. Each beam member 13 is mounted on the upperside and the lower side of the steel member 12 c constituting theoblique side of the panel supporting rack 12.

Next, as shown in FIG. 22, brace members 14, 15, and 16 are mounted. Inthis process, two brace members 14 and 15 are obliquely mounted from thepanel supporting rack 12, disposed at the center in the longitudinaldirection of the solar panel mounting stand 10, toward the panelsupporting racks 12 disposed on both sides of the central panelsupporting rack 12 so that a mountain shape is formed. Furthermore, thebrace member 16 is mounted such that it connects two piles 1 (pilebodies 2) disposed at the center in the longitudinal direction of thesolar panel mounting stand 10. The brace member 16 is mounted such thatit is inclined in the same direction of the steel member 12 cconstituting the oblique side of the panel supporting rack 12. Bracemembers 14, 15, and 16 are mounted using bolts and nuts, for example.Holes used for mounting work are provided beforehand in the panelsupporting racks 12 and the piles 1.

Moreover, brace members 14 and 15 may be mounted at any time after thepanel supporting racks 12 have been mounted. Similarly, the brace member16 may be mounted at any time after piles 1 have been installed.

Next, as shown in FIG. 23, panel receiving members 17 are mounted on thebeam members 13. The panel receiving members 17 are mounted such thatthey extend across two beam members 13. Furthermore, a plurality ofpanel receiving members 17 are mounted in the longitudinal direction ofthe solar panel mounting stand 10 at predetermined intervals. The panelreceiving members 17 are mounted using bolts and nuts, for example.Holes used for mounting work are provided beforehand in the beam members13 and the panel receiving members 17.

Thus, installation of the solar panel mounting stand 10 is completed.Thereafter, as shown in the front view of FIG. 24 and in the side viewof FIG. 25, a plurality of solar panels 31 are mounted on the solarpanel mounting stand 10. In FIG. 24, solar panels 31 appear to betransparent so that positional relationships among all the constituentmembers of the structure 20 and the solar panels 31 are clarified.

FIG. 26 shows specific structural examples where respective members arefastened by bolts and nuts. In FIG. 26(A) and FIG. 26(B), the panelsupporting rack 12 and the beam member 13 are fastened by a bolt 32 anda nut 33, and the beam member 13 and the panel receiving member 17 arefastened by a bolt 34 and a nut 35. And, the frame member 31 a of thesolar panel is fastened to the panel receiving member 17 by a bolt 36and a nut 37. Meanwhile, in FIG. 26(C), the panel supporting rack 12 andthe brace member 14 (15) are fastened by a bolt 38 and a nut 39; and inFIG. 26(D), the pile 1 that serves as a supporting leg 11 and the bracemember 16 are fastened by a bolt 40 and a nut 41. Moreover, the way offixing members is not limited to the fixing structure of using bolts andnuts, and for example, a fixing structure using fixing brackets notshown, or a fixing means such as welding can be adopted. However, whentaking into account the construction cost and material cost, it ispreferred that the fixing structure using bolts and nuts be adopted.

5. Effects of the Embodiment of the Present Invention

In the embodiment of the present invention, a pile 1 equipped with aprojecting portion 3 at the lower end of the pile body 2 is adopted andinstalled in the ground by an original method of “placing piles” insteadof using a commonly-known conventional “piling” method. Furthermore, theuse of this type of pile ensures the installation strength of the pile 1by burying the lower end of the pile 1 including the projecting portion3 in the ground. This makes troublesome “piling” work unnecessary.Furthermore, at locations where “piling” is difficult, it is possible toinstall solar panel mounting stands 10 without using expensive spiralpiles. As a result, it is possible to significantly reduce cost andlabor required for installing solar panel mounting stands. Consequently,it is possible to contribute to prevalence of solar power generation,resulting in further promotion of the use of natural energy.

Furthermore, using a pile 1 having a projecting portion 3 as asupporting leg 11 of the solar panel mounting stand 10, it is possibleto provide a sufficient resisting force against a pressing force causedby the weight of the solar panel mounting stand 10 and the solar panels31 and an opposite drawing force. Specifically, for the solar panelmounting stand 10, it is important to ensure sufficient installationstrength to resist strong wind pressure (lifting force) imposed on solarpanels 31 due to a typhoon or the like. In this regard, in the case ofpiles to be driven into the ground, piling is sometimes difficultdepending on the conditions of the ground, and the piles are relativelyeasy to pull off; thus, it is difficult to ensure sufficientinstallation strength against wind pressure caused by strong wind.Meanwhile, when a solar panel mounting stand 10 is formed using piles 1of this embodiment, as described above, it is possible to provide asufficient resisting force against both the pressing force and thedrawing force; consequently, it is possible to ensure superiorinstallation strength specifically against wind pressure caused bystrong wind.

For reference, tensile test was conducted for the piles 1 installed bythe method of this embodiment, and better results than expected wereobtained.

In the tensile test, the pile body 2 of the pile 1 was made of a steelpipe with a diameter of 50 mm, and the projecting portion 3 was made ofa 500-mm square steel plate. Furthermore, the lower end of the pile body2 was buried in the soil in about 1.8 m depth, and the pile 1 wasvertically pulled by applying a 20-kN pulling force. Consequently, thedisplacement amount (ascending amount) of the pile 1 was only 14 mm.This is the test result obtained from one pile 1. Therefore, asdescribed above, when six piles 1 are used as supporting legs 11 to forma solar panel mounting stand 10, it can withstand at least a 120-kNpulling force in total.

Furthermore, according to the embodiment of the present invention, evenif the solar panel mounting stand installation site is on undulatingground, installation of piles 1 can be conducted without problems.Hereinafter, a detailed description will be given.

The solar panel mounting stand installation site is not always on levelground. Specifically, a large-scale solar-power plant like mega solarrequires wide expanse of ground to lay a large number of solar panels.However, appropriate expanses of level ground are sometimes difficult tofind. Furthermore, if undulating ground is to be leveled, a large-scaleland grading project is necessary, resulting in enormous cost and labor.

If piles are installed by “piling” into the undulating ground, there isa concern that the following adverse conditions occurs. For example, inthe case of driving piles into the ground, as shown in FIG. 27, when aplurality of piles 51 having the same length are driven into the unevenground so that the upper ends of the piles are aligned in height, it isnecessary to drive piles 51 located in the higher-level ground deeperinto the ground than the piles 51 located in the lower-level ground.Therefore, when piling depth D1 required for inhibiting the pull-off ofpiles is ensured at the lower-level ground, it is necessary to drivepiles 51 into the higher-level ground at a deeper depth of D1+D2.However, in the ground where piling is difficult, even if piles 51 aresuccessfully driven into the lower-level ground at desired depth D1, itmay not be possible to drive piles 51 into the higher-level ground atthe desired depth D1+D2. As a result, the height of the upper end ofeach pile 51 differs by the dimension D2.

Meanwhile, according to this embodiment, the soil at the installationsite is dug out and piles 1 are installed therein, even if the ground isundulating, by changing the excavation (hole) depths D4 and D5 in thehigher-level ground and in the lower-level ground as shown in FIG. 28,it is possible to install piles 1 with the upper ends thereof aligned atthe same height. Accordingly, it is not necessary to level the ground.Therefore, it is possible to significantly reduce the total costrequired for installing solar panel mounting stands, specifically, totalcost for installing solar panel mounting stands on the undulating groundor on the inclined ground. Furthermore, as for the undulating ground, itis possible to successfully cope with nearly 1-meter undulation.

Furthermore, in the embodiment of the present invention, a plurality ofpiles 1 are supported by a structure 20, and while this condition ismaintained, each pile 1 comes in contact with the planned installationground surface 19 and is securely fixed by the soil used for refilling.Therefore, it is possible to precisely install a plurality of piles 1 atthe installation site of the solar panel mounting stand 10. Meanwhile,for example, when driving piles into the ground, respective piles needto be driven into the ground one by one. In this case, it is verydifficult to precisely drive piles at desired locations at desireddepth. Consequently, deviation tends to occur in the relative positionsof the plurality of piles. Therefore, in the process of mounting membersconstituting a framework of the solar panel mounting stand, on aplurality of piles, positions of the holes provided in the members aregreatly misaligned, which could possibly prohibit mounting of themembers. Even if all members can be mounted, distortion may occur in theentire solar panel mounting stand.

Meanwhile, by using the method of installing a solar panel mountingstand according to the embodiment of the present invention, piles 1 aresecurely fixed by compacting the refilling soil while maintaining therelative positional relationships of the plurality of piles 1 by usingthe structure 20; therefore, it is possible to precisely install aplurality of piles 1. Consequently, it is possible to mount all membersas prescribed without causing the entire mounting rack to distort.Furthermore, since a plurality of piles 1 can be installedsimultaneously at the installation site of the solar panel mountingstand 10, construction efficiency significantly increases. As a result,it is possible to simultaneously reduce the installation cost andincrease pile installation accuracy.

Furthermore, in the method of installing a solar panel mounting standaccording to the embodiment of the present invention, since thestructure 20 that supports a plurality of piles 1 is hoisted by a craneand transported to the installation site of the solar panel mountingstand 10, an unnecessary force is not imposed on the piles 1 duringtransportation. Therefore, relative positions of the plurality of piles1 do not change. Furthermore, while piles are hoisted by a crane (pilesstay afloat), it is possible to move the positions of entire piles inthe horizontal direction without applying a large force while therelative positions of the plurality of piles 1 are maintained.Therefore, it is possible to easily position the projecting portions 3of respective piles 1 on the corresponding planned installation groundsurfaces 19.

6. Modified Example, Etc.

Moreover, the technical scope of the present invention is not limited tothe aforementioned embodiment, and includes variety of modifications andalterations within a scope capable of deriving specific effects obtainedby constituting features of the invention and a combination of them.

For example, in the above embodiment, a cross-sectional shape of thepile body 2 is circular; however, the present invention is not limitedthereto, and the cross-sectional shape of the pile body 2 may be aprismatic column such as a quadrangular prism.

Furthermore, the planar shape of the projecting portion 3 is not limitedto a square or other quadrangles, and can be of any shape as long as itreceives the load of the refilling soil on the surface thereof; forexample, it can be a polygon, circle, oval, flower-petal shape, orcross-like figure. Furthermore, in addition to providing the projectingportion 3 at the lower end of the pile body 2, two or three projectingportions may be disposed at the lower end portion of the pile body 2,which is eventually buried in the soil, at certain intervals in thelongitudinal direction of the pile body 2.

Furthermore, it is preferred that the projecting portion 3 be formedinto a flat plate-like shape so as to be a simple structure andefficiently receive the load of the soil; however, the shape is notlimited to the flat plate-like shape. For example, although not shown, apart of or the entire outer circumference edge of the projecting portion3 may be bent upward. Furthermore, when the projecting portion 3 isformed into a plate-like shape, instead of disposing the projectingportion 3 at a right angle with regard to the central axis of the pilebody 2, the projecting portion 3 may be disposed slightly inclined(preferably, an inclined angle of more than 0 degrees, and equivalent toor less than 30 degrees). However, since piles according to the presentinvention are not driven or screwed into the ground, spiral-shaped pilesare excluded.

Furthermore, members of the framework mounted onto the supporting legs11 (piles 1) of the solar panel mounting stand 10 are not limited to theaforementioned members, and they may be any member to which solar panelscan be mounted. Furthermore, in this case, the shape of the couplingportion 4 provided at the upper end of the pile body 2 can be changedaccording to the member mounted thereon; and it is also possible tomount framework members on the pile body 2 using separate mountingfittings or the like without providing a coupling portion 4. Therefore,the coupling portion 4 may be provided as needed.

However, by adopting a configuration in which a coupling portion 4 isintegrally provided at the upper end of the pile body 2, and a trianglepanel supporting rack 12 is placed on top of the coupling portion 4 andfixed, it is easy to obliquely mount panel receiving members 17, and themechanical strength (rigidity, etc.) of the entire mounting rack can beincreased. Therefore, it is possible to reduce construction cost andmaterial cost as much as possible, resulting in reduction of the totalcost required for installing the solar panel mounting stand 10.

Furthermore, because panel receiving members 17 are made of lip groovesteel, by changing the dimensions (mainly length) of the actually-usedlip groove steel, hole positions, the number of members, etc., it ispossible to mount different manufacturers' solar panels or change thenumber of solar panels made by the same manufacturer.

Furthermore, constituent material of the solar panel mounting stand isnot limited to steel, but it can be any material as long as it satisfiesthe mechanical strength, durability, antiweatherability, etc., requiredfor the solar panel mounting stand; for example, other metal (includingalloy) such as stainless-steel, aluminum, etc., and plastic such asreinforced plastic can be used.

<7. Other Preferred Aspect of the Present Invention>

A pile of the present invention is preferable for the use as asupporting leg of the solar panel mounting stand; however, the pile canbe widely applied to other use as well. For example, the pile accordingto the present invention can be used when an advertising display or asign is installed on the ground. A preferred embodiment of the presentinvention in that case will be additionally described.

(Supplementary Description)

A pile includes a columnar pile body, at least the lower end portion ofwhich is buried in the soil, and a non-spiral-shaped projecting portionprovided at the lower end of the pile body so that it projects in theradial direction of the pile body, wherein when the lower end portion ofthe pile body is buried in the soil, the projecting portion inhibits thepull-off of the pile body under load of the soil.

1. A method of installing a solar panel mounting stand using a pile as asupporting leg, the pile comprising: a columnar pile body, at least alower end side thereof being buried in the soil when a solar panelmounting stand equipped with a plurality of supporting legs is installedon the ground; and a non-spiral-shaped projecting portion provided at alower end of the pile body in a state projected in a radial direction ofthe pile body and configured to inhibit a pull-off of the pile bodyunder a load of the soil when the lower end side of the pile body isembedded in the soil; the method comprising: a first step of forming aninstallation scheduled surface on which the plurality of piles arescheduled to be installed at a position deeper than an original groundsurface, by digging the soil of an installation site of the solar panelmounting stand; a second step of installing the plurality of piles atthe installation site by supporting the plurality of piles in a state ofbeing relatively aligned, using a pile installation structure, and whilemaintaining such a supporting state, transporting the plurality of pilesto the installation site of the solar panel mounting stand integrallywith the pile installation structure, and placing the projectingportions, which are formed at lower ends of the plurality of piles, onthe installation scheduled surface corresponding to each projectingportion, and thereafter refilling the installation site with soil; athird step of removing the pile installation structure from theplurality of piles; and a fourth step of assembling a member as aframework of the solar panel mounting stand, using the plurality ofpiles.
 2. A solar panel mounting stand installation method according toclaim 1, wherein in the second step, the pile installation structuresupporting the plurality of piles, is hoisted by a crane and transportedto the installation site of the solar panel mounting stand.
 3. A pileused as a supporting leg when a solar panel mounting stand equipped witha plurality of supporting legs is installed, comprising: a columnar pilebody; and a non-spiral-shaped projecting portion provided at a lower endof the pile body in a state projected in a radial direction of the pilebody, wherein at least a lower end side of the pile body is buried inthe soil when the solar panel mounting stand is installed; and theprojecting portion is configured to inhibit a pull-off of the pile bodyunder a load of the soil when the lower end side of the pile body isembedded in the soil.
 4. The pile according to claim 3, wherein theprojecting portion is formed into a plate-like shape having a largerexternal size than an outer diameter of the pile body.
 5. The pileaccording to claim 3, wherein a coupling portion is provided on an upperend of the pile body, for assembling a member as a framework of thesolar panel mounting stand.
 6. A solar panel mounting stand equippedwith a plurality of supporting legs, wherein a pile is used as asupporting leg, said pile comprising: a columnar pile body, at least alower end portion thereof being buried in the soil; and anon-spiral-shaped projecting portion provided at a lower end of the pilebody in a state projected in a radial direction of the pile body, andconfigured to inhibit a pull-off of the pile body under the load of thesoil when the lower end side of the pile body is embedded in the soil.7. The pile according to claim 4, wherein a coupling portion is providedon an upper end of the pile body, for assembling a member as a frameworkof the solar panel mounting stand.